node_modules/thing/index.js
let x = "SSSSSS";
let y = "SSSSWWWWW";
let z = function()
{
alert("ZZZZZ");
}
exports.x = x;
exports.y = y;
exports.z = z;
App.js
import logo from './logo.svg';
import './App.css';
import {useEffect} from 'react';
import {x,y,z} from 'thing';
function App() {
useEffect(()=>{
alert(x);
z();
})